Key Technologies And Verification Of 20Gbps Terahertz Wireless Data Transmission

As wireless data traffic grows exponentially,every layer of the network model faces speed-up issues.However,the existing physical layer frequency band is difficult to carry the speed requirements,and the processing of high-speed data by complex software protocol stacks such as TCP/IP will occupy a large amount of CPU resources and processing cycles.In this regard,the terahertz communication technology with the potential of Tbps data transmission and the protocol offload technology that implements the protocol stack by dedicated hardware have become hotspots in high-speed communication research.This paper is dedicated to building a network layered model through the above two technologies to achieve high-speed and reliable two-way wireless communication.The main work is as follows:First,analyze the point-to-point wireless data transmission scenario of ultra-highspeed sensors,and design a communication model.From the perspective of bandwidth utilization,analog and digital circuit complexity,etc.,a zero-IF architecture is selected at the physical layer,and a simplified channel model is obtained by analyzing the radio frequency channel.Facing the requirement of reliable file transmission,TCP and NFS protocols are selected in the transport layer and application layer.Finally,a network layered model is designed on the basis of terahertz frequency division duplex zero-IF transceiver and TCP,NFS protocol offloading.Second,for the physical layer,the terahertz wireless communication transceiver architecture is given,and the channel equalization algorithm is designed based on the channel model.For frequency-dependent IQ imbalance channels,a frequency-domain LS-LMS(2Tap)channel equalization algorithm is proposed by combining the advantages of LS algorithm with less training overhead and less performance degradation of LMS algorithm.For frequency-dependent IQ imbalance and small carrier frequency offset channels,a frequency-domain LS-LMS(4Tap)channel equalization algorithm is proposed,which includes a frequency-domain frequency offset estimation and correction structure with less resource consumption.Third,for the upper layer,on the basis of the TCP/IP offloading engine,functions such as TCP-Multi APP interface,NFS client,and multi-channel file management are designed.The TCP-Multi APP interface provides a unified pipeline interface for multiple applications to access TCP.The NFS client can achieve efficient data transmission in the writing phase by obtaining file handles in advance and asynchronous non-blocking transmission.Multi-channel file management realizes multi-channel data efficient caching through design such as address wrapping and reducing cross-page access.Fourth,use the FPGA digital verification platform to realize the above key technologies,build 200/220 GHz terahertz frequency division duplex wireless communication,100 Gbps Ethernet TCP/IP-NFS verification system and test various performances.The former measures MERs of 19.5d B and 18.3d B in the 200/220 GHz frequency band and an outdoor distance of 750 m,and the block error rate after decoding is less than,achieving an air interface rate of 20.8Gbps×2 and a service rate of12.78Gbps×2.The latter measures the network speed up to 98 Gbps under the conditions of TCP clock 195.3125 MHz,bit width 512 b,and maximum packet length 8960 B,and NFS file writing speed up to 90 Gbps.This paper designs,implements and verifies some key technologies of terahertz wireless communication and protocol offloading,which has engineering reference significance in the development of terahertz network models.